32.1 Electrical Forces and Charges ·Electrical force- a force that one charge applies on another. ·Similar charges repel, opposite charges attract. http://upload.wikimedia.org/wikipedia/commons/1/14/Magnetic_field_of_bar_magnets_repelling.png ·Charge- the basic electrical property in which like attractions between electrons or protons is seen. 32.2 Conservation of Charge ·Conservation of charge- when net electric charge is neither created nor destroyed but can be moved from one material to another. 32.3 Coulomb’s Law ·Coulomb’s law: The relationship between electrical force, charges, and distance: The electrical force between two charges varies directly as the product of the charges and inversely as the square of the distance between them (Hewitt, 505). ·Coulomb: The SI unit of charge, one coulomb is equal to the total charge of 6.24 * 10^18 electrons. ·Law can be expressed as: F= k(q1q2/d^2) 32.4 Conductors and Insulators ·Conductor: A Material through which heat can be transferred. Good conductors of heat are good charge conductors. oElectrons are loose oExamples: metal ·Semiconductors: materials that can be made to behave as insulators and as conductors ·Superconductors: material that has endless conductivity at low temperatures, so that a charge can flow through it easily. ·Insulator: A material that is a poor conductor of heat and that slows the transfer of heat and electricity. oExamples: Rubber, glass, and wood 32.5 Charging by Friction and Contact ·Charging by Contact: When a charged rod is placed with a neutral object, some charge will transfer to the neutral object. oExample: shocking someone http://www.sandaigprimary.co.uk/pivot/images/static_balloon.jpg 32.6 Charging by Induction
Induced: A term applied to electric charge that has been transferred onto an object because of the presence of a charged object near by.
Induction: The charging of an object without any direct contact
Grounding: when charges move off or on to a conductor by touching it
32.7 Charge Polarization
Electrically polarized: Term applied to an atom or molecule in which the charges are lined up so that one side is more positive or negative than the other side
The reason an inflated balloon sticks to a wall once rubbed on your hair is because the charge on the balloon induces an opposite surface charge on the wall.
To summarize how objects are electrically charged, there are three ways:
Friction
Contact
Induction
Works Cited
Hewitt, Paul G. Conceptual Physics: With Expanded Technology The High School Physics Program. New York: Addison-Wesley Pub (Sd), 1999.
Electrostatics
32.1 Electrical Forces and Charges
· Electrical force- a force that one charge applies on another.
· Similar charges repel, opposite charges attract.
http://upload.wikimedia.org/wikipedia/commons/1/14/Magnetic_field_of_bar_magnets_repelling.png
· Charge- the basic electrical property in which like attractions between electrons or protons is seen.
32.2 Conservation of Charge
· Conservation of charge- when net electric charge is neither created nor destroyed but can be moved from one material to another.
32.3 Coulomb’s Law
· Coulomb’s law: The relationship between electrical force, charges, and distance: The electrical force between two charges varies directly as the product of the charges and inversely as the square of the distance between them (Hewitt, 505).
· Coulomb: The SI unit of charge, one coulomb is equal to the total charge of 6.24 * 10^18 electrons.
· Law can be expressed as: F= k(q1q2/d^2)
32.4 Conductors and Insulators
· Conductor: A Material through which heat can be transferred. Good conductors of heat are good charge conductors.
o Electrons are loose
o Examples: metal
· Semiconductors: materials that can be made to behave as insulators and as conductors
· Superconductors: material that has endless conductivity at low temperatures, so that a charge can flow through it easily.
· Insulator: A material that is a poor conductor of heat and that slows the transfer of heat and electricity.
o Examples: Rubber, glass, and wood
32.5 Charging by Friction and Contact
· Charging by Contact: When a charged rod is placed with a neutral object, some charge will transfer to the neutral object.
o Example: shocking someone
http://www.sandaigprimary.co.uk/pivot/images/static_balloon.jpg
32.6 Charging by Induction
- Induced: A term applied to electric charge that has been transferred onto an object because of the presence of a charged object near by.
- Induction: The charging of an object without any direct contact
- Grounding: when charges move off or on to a conductor by touching it
32.7 Charge Polarization- Electrically polarized: Term applied to an atom or molecule in which the charges are lined up so that one side is more positive or negative than the other side
- The reason an inflated balloon sticks to a wall once rubbed on your hair is because the charge on the balloon induces an opposite surface charge on the wall.
- To summarize how objects are electrically charged, there are three ways:
- Friction
- Contact
- Induction
Works CitedHewitt, Paul G. Conceptual Physics: With Expanded Technology The High School Physics Program. New York: Addison-Wesley Pub (Sd), 1999.